Calculating machine



Dec. 12, 1950 N. T. PIERCE CALCULATING MACHINE Filed June 11, 1949 l4 'DlvlDE g MULTIPLY flaribzz 17 6 :2 pm;-

V Wezzibp Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE CALCULATING MACHINE Norton T. Pierce, Reading, Mass. Application June 11, 1949, Serial No. 98,430

6 Claims.

My invention relates to calculating machines, and in particular to calculating machines for solving problems in multiplication, division, proportions, square roots, or a combination of multiplications and divisions in one problem.

The conventional way of solving such problems for practical engineering, scientific, and business purposes is to use a straight slide rule or circular slide rule of some sort, utilizing the logarithmic principle of the addition and subtraction of the logarithms of numbers for the multiplication and division of those numbers.

These slide rules all require both hands for their operation and are somewhat inconvenient at times, particularly when using one hand to record answers during a series of calculations. One of the primary objects of my invention is, therefore, to provide a small desk model calculating machine which can be operated easily and quickly with one hand, leaving the other free at all times during the calculation.

Another object of this invention is to provide a machine which can perform any number of alternate multiplications and divisions in one problem merely by shifting a single convenient lever and rotating a single knob to set the appropriate numbers on a scale opposite a fixed index-line.

I attain these objects by mechanism illustrated in the accompanying drawing, in which:

Fig. 1 is a front elevation.

Fig. 2 is a vertical sectional view taken on line 2-2 in Fig. 1.

Fig. 3 is a partially cut-away view taken substantially on line 3'-3 in Fig. 2, showing the cylinder clamping lever and linkage.

As shown in the drawing, this calculator consists of three coaxially disposed cylindrical drums or annular bands III, N and I2 all mounted in parallel relation on a common shaft 21 and free to turn thereon. Drums I0 and I2 each have fixed to them, or integral with them, bevel gears 26 and 30, respectively. The center drum carries the small bevel gear 29 which is free to rotate on its shaft 28, arranged at right angles to main shaft 21.

Means is provided for rotating the drums I0, I and I2, which includes a turning knob l3 fixedly mounted on shaft 2|, arranged below the drums, and preferably at right angles to shaft 21. A friction wheel having a friction surface, such as of rubber, is also fixed on shaft 2| which engages the underside of drum l2 for rotating the latter.

Means is provided whereby drums W or H may be clamped, which includes a lever 22 pivoted at 32 on fixed bracket 33 and having two friction pads 3| fixed thereto. This lever is moved from one side to the other by means of hand lever |4 pivoted at 24 and connected by a suitable linkage 34 fastened to lever M by pin 23 and to arm 22 by pin 35. Arm 22 is constrained to stay in either side position, clamping either drums in or H, by means of a toggle spring 25, which is fixed at the bottom in base l6 and connected at the top to arm 22.

The drums l0 and I2 each have fixed to their peripheral edges or molded integrally therein, a complete logarithmic cycle scale such as is found on the (3" or D scales of a conventional slide rule. Drum N has a scale consisting of two logarithmic cycles, as found on the double-cycle scale commonly called the A or B scales of a conventional slide rule, each cycle being half as long as the cycles on drums l0 and I2. The scales are viewed through a window l8 fastened in the housing l5 and the scale numbers are set opposite the fixed index-line inscribed on window la. The base of the housing I6 can also act as a bearing for shafts 21 and 2| and is fixed by suitable means to the housing l5.

In operation for multiplication, such as R S=P product P then appears opposite the index-- line on scale For division, such as the numbers are set in a similar manner, the number T being set on scale while drum I0 is clamped, the number U then being set on scale l2 while drum II is clamped, and the answer V appearing on scale I0.

For a long combination of multiplications and divisions in one problem, a number is first set on scale N), then all succeeding multiplications and divisions are performed alternately by merely shifting the lever M to either Multiply or Divide position and setting the appropriate numbers on scale |2. Answer appears on either scale H! or H depending on whether last operation was division or multiplication.

I claim:

1. In a calculating machine, a fixed index line thereon, a series of three cylindrical drums rotatably mounted in parallel relation on a common shaft and having scale markings on their peripheral edges, said drums being rotatable with respect to said fixed index line, a differential gearing connecting said cylindrical drums, a turning knob engaging an outer drum for rotating it :and ,:-a locking device "ior ialternately locking one of the other two drums against r tation, as desired, as the third drum is rotated through said turning knob.

2. In a calculating machine, a fixedrindex line thereon, a series of three cylindrical drums rotatably mounted in parallel relation-on a-common shaft and having scale markings on their peripheral edges said drums being rotatable with respect to said fixed index line, a differential gearing connecting said cylindrical drums, a turning knobrengaging an router drum rforrotatingisaid drums'ithrough said differential gearingzan'd a tlocking i device for alternately docking one 'ofthe other two :drums against rotation, as desired, :as the third "drum and the unlocked drum are rotated (through said "turning knob.

13. ..In: a calculating :machine, a window, a fixed index :lineithereon, a'series of three cylindrical drums =rotatably mounted in parallel relation on a common shaft and having scale markings on their :peripheral edges said drums being arc-- tatable with'irespect tocsaid fixed index line, a bevel vgearrdifferential connectingsaid cylindrical drums, Fa'turningiknob engaging an outer'd'rum for=rotatingsaid'drumsthrough said bevel gear differential and a locking device for alternately locking one of the other "two drums against rotationyas deSiI-ecL-as the=third=drum and the unlocked drum are rotated through said turning knob.

'4.In a calculating 'machine, a fixed index line thereon, a series 'of' three cylindrical drums rotatably mounted in parallel relation on a common shaft and having scale markings on their peripheral edges, said drums being rotatable With respectto'saidflxed indexline, bevel gears on the inner surfaces of the outer drums and a bevel gear rotatably-mounted in the inner drum connecting the bevel gears on the outer drums, a turning knob engaging an outer drum for difierentially rotating said drums through said bevel gears, and a locking device for alternately locking one of the other two drums against rotation, as desired, as the third drum and the unlocked drum are rotated through said turning knob.

5. In a calculating machine, a fixed index line thereon, a common shaft, a series ofthree cylindrical drums rotatably mounted in parallel relation on said shaft and having scale markings on their peripheral edges, said drums being ro- 'tatable with respect to said index line, difierential gearing connecting said cylindrical drums, "a turning knob rotatably mounted on a shaft at right angles to the shaft supporting said drums, and a locking device for alternately looking one ofthe other two drums against rotation, as desired, as the third drum and the unlocked drum are rotated through said turning knob and 'difierential gearing.

'6. In:a calculating machine, afixed'indexline thereon,'a series of'three cylindricaldrumgmotatably mounted in parallel relation onacommonshaft and having scale markingson'their peripheral edges said'drums heingrotatable with respect to said fixed index line, a differential gearing connecting said cylindrical drums, a turningtknob engaging an outer drum .for rotating-said drums through said diiferential gearing and a locking device operating a pivoted frictional clamp for alternately lockingone of the other two drums against rotation, as de sired, as the third drum andthe unlocked drum. arerotated 1 through. said turning knob.

NORTONT. PIERCE.

REFERENCES GI-TED The following references'are of record in the file of this patent:

UNITED STATES PATENTS Number Name iDate 1,726,370 Smith Aug. 27, .1929 2,285,774 .Horner June-9, 19.42 2,454,987 Bradner Nov. 30,1948 

